The present invention relates to a catalytic material and to a process for preparing the same. More specifically, the present invention relates to a process for adding a hydrogenation component to a non-zeolitic molecular sieve (NZMS) in order to produce a catalyst material having higher activity for catalytic conversions than similar materials prepared using conventional methods.
The non-zeolitic molecular sieve to which the present invention is directed is a crystalline material having a three-dimensional microporous framework of AlO.sub.2 and PO.sub.2 tetrahedral units. Crystalline aluminophosphate compositions are disclosed in U.S. Pat. No. 4,310,440. Silicon substituted aluminophosphates are disclosed in U.S. Pat. No. 4,440,871. Metal substituted aluminophosphates are disclosed in U.S. Pat. No. 4,853,197. Each of these patents is incorporated herein by references for all purposes.
Catalysts containing a NZMS frequently contain a hydrogenation component. U.S. Pat. No. 4,440,871 teaches SAPO catalyst compositions which contain a hydrogenation promoter such as platinum, palladium, tungsten and molybdenum. U.S. Pat. No. 4,906,351 teaches a hydrodewaxing process using a catalyst comprising an effective amount of at least one NZMS selected from the group consisting of SAPO, ELAPSO, MeAPO, FeAPO, TiAPO and ELAPO molecular sieves, and containing a hydrogenation component, which may be selected from the group of hydrogenation catalysts consisting of one or more metals of Group VIB and Group VIII. U.S. Pat. No. 4,906,351 further teaches adding the hydrogenation component to the catalyst.
U.S. Pat. No. 5,282,958 provides an example of a method for preparing an intermediate pore molecular sieve dewaxing catalyst by ion exchanging a catalyst support with 0.5 wt % palladium or platinum from an aqueous solution of Pd(NH.sub.3).sub.4 (NO.sub.3).sub.2 or Pt(NH.sub.3).sub.4 (NO.sub.3).sub.2. U.S. Pat. No. 5,246,566 teaches adding a Pt promoter to SAPO-11 bound with 35% Catapal by impregnating the extrudates with 0.5% Pt as Pt(NO.sub.3).sub.4 Cl.sub.2.H.sub.2 O. U.S. Pat. No. 5,139,647 teaches impregnating extrudates of SAPO-11 bound with Catapal alumina using an aqueous solution of Pd(NH.sub.3).sub.4 (NO.sub.3).sub.2.
U.S. Pat. No. 4,710,485 teaches growing crystals of a silicoaluminophosphate molecular sieve from an aqueous medium containing a water soluble compound of a Group VIII metal. Thus, the Group VIII metal is occluded within the pores of the molecular sieve by incorporating a water-soluble salt of the desired metal into the forming solution of the molecular sieve and then growing the silicoaluminophosphate molecular sieve crystals by subjecting the reaction mixture to hydrothermal treatment, and dehydrating the resulting product.
With the cost of preparing catalytic materials continually increasing, it is vitally important to develop new methods of preparing catalysts for improved activity and selectivity. The present method, directed to non-zeolitic molecular sieve containing catalysts, provides a surprising improvement over conventional catalyst-preparation methods.